One thing to consider, looking at most, if not all, the aftermarket MII based K members out there is that the inner LCA pivots are not nearly as well braced as the factory K member. I suspect over time usage will spread those inner pivots outward.
That can be tested rather easily.
These tests would not be destructive in nature unless the frame is substantially under built and fragile.
I'm not interested in testing them to failure. That makes for good video but that's about it. Simple deflection tests would be sufficient. The assemblies should have the ability to deform slightly and return to their original state.
The fun part of these kinds of tests are when you use a long lever arm to apply a load (like Goody's example). The end of that arm can sweep a pretty wide arc.
Years ago, I was present for frame testing on light duty trucks. You could use the Toyota frame like a diving board.
